nsz Git - musl/blob - src/ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <stdint.h>
   7 #include <elf.h>
   8 #include <sys/mman.h>
   9 #include <limits.h>
  10 #include <stdint.h>
  11 #include <fcntl.h>
  12 #include <sys/stat.h>
  13 #include <errno.h>
  14 #include <limits.h>
  15 #include <elf.h>
  16 #include <link.h>
  17 #include <setjmp.h>
  18 #include <pthread.h>
  19 #include <ctype.h>
  20 #include <dlfcn.h>
  21 #include "pthread_impl.h"
  22 #include "libc.h"
  23
  24 static int errflag;
  25 static char errbuf[128];
  26
  27 #ifdef SHARED
  28
  29 #if ULONG_MAX == 0xffffffff
  30 typedef Elf32_Ehdr Ehdr;
  31 typedef Elf32_Phdr Phdr;
  32 typedef Elf32_Sym Sym;
  33 #define R_TYPE(x) ((x)&255)
  34 #define R_SYM(x) ((x)>>8)
  35 #else
  36 typedef Elf64_Ehdr Ehdr;
  37 typedef Elf64_Phdr Phdr;
  38 typedef Elf64_Sym Sym;
  39 #define R_TYPE(x) ((x)&0xffffffff)
  40 #define R_SYM(x) ((x)>>32)
  41 #endif
  42
  43 #define MAXP2(a,b) (-(-(a)&-(b)))
  44 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  45
  46 struct debug {
  47         int ver;
  48         void *head;
  49         void (*bp)(void);
  50         int state;
  51         void *base;
  52 };
  53
  54 struct dso {
  55         unsigned char *base;
  56         char *name;
  57         size_t *dynv;
  58         struct dso *next, *prev;
  59
  60         Phdr *phdr;
  61         int phnum;
  62         int refcnt;
  63         Sym *syms;
  64         uint32_t *hashtab;
  65         uint32_t *ghashtab;
  66         int16_t *versym;
  67         char *strings;
  68         unsigned char *map;
  69         size_t map_len;
  70         dev_t dev;
  71         ino_t ino;
  72         signed char global;
  73         char relocated;
  74         char constructed;
  75         char kernel_mapped;
  76         struct dso **deps, *needed_by;
  77         char *rpath_orig, *rpath;
  78         void *tls_image;
  79         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  80         void **new_dtv;
  81         unsigned char *new_tls;
  82         int new_dtv_idx, new_tls_idx;
  83         struct dso *fini_next;
  84         char *shortname;
  85         char buf[];
  86 };
  87
  88 struct symdef {
  89         Sym *sym;
  90         struct dso *dso;
  91 };
  92
  93 #include "reloc.h"
  94
  95 void __init_ssp(size_t *);
  96 void *__install_initial_tls(void *);
  97 void __init_libc(char **, char *);
  98
  99 static struct dso *head, *tail, *ldso, *fini_head;
 100 static char *env_path, *sys_path;
 101 static unsigned long long gencnt;
 102 static int ssp_used;
 103 static int runtime;
 104 static int ldd_mode;
 105 static int ldso_fail;
 106 static int noload;
 107 static jmp_buf *rtld_fail;
 108 static pthread_rwlock_t lock;
 109 static struct debug debug;
 110 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 111 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 112
 113 struct debug *_dl_debug_addr = &debug;
 114
 115 #define AUX_CNT 38
 116 #define DYN_CNT 34
 117
 118 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 119 {
 120         memset(a, 0, cnt*sizeof(size_t));
 121         for (; v[0]; v+=2) if (v[0]<cnt) {
 122                 a[0] |= 1ULL<<v[0];
 123                 a[v[0]] = v[1];
 124         }
 125 }
 126
 127 static int search_vec(size_t *v, size_t *r, size_t key)
 128 {
 129         for (; v[0]!=key; v+=2)
 130                 if (!v[0]) return 0;
 131         *r = v[1];
 132         return 1;
 133 }
 134
 135 static uint32_t sysv_hash(const char *s0)
 136 {
 137         const unsigned char *s = (void *)s0;
 138         uint_fast32_t h = 0;
 139         while (*s) {
 140                 h = 16*h + *s++;
 141                 h ^= h>>24 & 0xf0;
 142         }
 143         return h & 0xfffffff;
 144 }
 145
 146 static uint32_t gnu_hash(const char *s0)
 147 {
 148         const unsigned char *s = (void *)s0;
 149         uint_fast32_t h = 5381;
 150         for (; *s; s++)
 151                 h = h*33 + *s;
 152         return h;
 153 }
 154
 155 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 156 {
 157         size_t i;
 158         Sym *syms = dso->syms;
 159         uint32_t *hashtab = dso->hashtab;
 160         char *strings = dso->strings;
 161         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 162                 if ((!dso->versym || dso->versym[i] >= 0)
 163                     && (!strcmp(s, strings+syms[i].st_name)))
 164                         return syms+i;
 165         }
 166         return 0;
 167 }
 168
 169 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 170 {
 171         Sym *syms = dso->syms;
 172         char *strings = dso->strings;
 173         uint32_t *hashtab = dso->ghashtab;
 174         uint32_t nbuckets = hashtab[0];
 175         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 176         uint32_t h2;
 177         uint32_t *hashval;
 178         uint32_t i = buckets[h1 % nbuckets];
 179
 180         if (!i) return 0;
 181
 182         hashval = buckets + nbuckets + (i - hashtab[1]);
 183
 184         for (h1 |= 1; ; i++) {
 185                 h2 = *hashval++;
 186                 if ((!dso->versym || dso->versym[i] >= 0)
 187                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 188                         return syms+i;
 189                 if (h2 & 1) break;
 190         }
 191
 192         return 0;
 193 }
 194
 195 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 196 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 197
 198 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 199 {
 200         uint32_t h = 0, gh = 0;
 201         struct symdef def = {0};
 202         if (dso->ghashtab) {
 203                 gh = gnu_hash(s);
 204                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 205         } else {
 206                 h = sysv_hash(s);
 207                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 208         }
 209         for (; dso; dso=dso->next) {
 210                 Sym *sym;
 211                 if (!dso->global) continue;
 212                 if (dso->ghashtab) {
 213                         if (!gh) gh = gnu_hash(s);
 214                         sym = gnu_lookup(s, gh, dso);
 215                 } else {
 216                         if (!h) h = sysv_hash(s);
 217                         sym = sysv_lookup(s, h, dso);
 218                 }
 219                 if (!sym) continue;
 220                 if (!sym->st_shndx)
 221                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 222                                 continue;
 223                 if (!sym->st_value)
 224                         if ((sym->st_info&0xf) != STT_TLS)
 225                                 continue;
 226                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 227                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 228
 229                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 230                 def.sym = sym;
 231                 def.dso = dso;
 232                 if (sym->st_info>>4 == STB_GLOBAL) break;
 233         }
 234         return def;
 235 }
 236
 237 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 238 {
 239         unsigned char *base = dso->base;
 240         Sym *syms = dso->syms;
 241         char *strings = dso->strings;
 242         Sym *sym;
 243         const char *name;
 244         void *ctx;
 245         int type;
 246         int sym_index;
 247         struct symdef def;
 248
 249         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 250                 type = R_TYPE(rel[1]);
 251                 sym_index = R_SYM(rel[1]);
 252                 if (sym_index) {
 253                         sym = syms + sym_index;
 254                         name = strings + sym->st_name;
 255                         ctx = IS_COPY(type) ? head->next : head;
 256                         def = find_sym(ctx, name, IS_PLT(type));
 257                         if (!def.sym && sym->st_info>>4 != STB_WEAK) {
 258                                 snprintf(errbuf, sizeof errbuf,
 259                                         "Error relocating %s: %s: symbol not found",
 260                                         dso->name, name);
 261                                 if (runtime) longjmp(*rtld_fail, 1);
 262                                 dprintf(2, "%s\n", errbuf);
 263                                 ldso_fail = 1;
 264                                 continue;
 265                         }
 266                 } else {
 267                         sym = 0;
 268                         def.sym = 0;
 269                         def.dso = 0;
 270                 }
 271                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 272                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 273                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 274         }
 275 }
 276
 277 /* A huge hack: to make up for the wastefulness of shared libraries
 278  * needing at least a page of dirty memory even if they have no global
 279  * data, we reclaim the gaps at the beginning and end of writable maps
 280  * and "donate" them to the heap by setting up minimal malloc
 281  * structures and then freeing them. */
 282
 283 static void reclaim(unsigned char *base, size_t start, size_t end)
 284 {
 285         size_t *a, *z;
 286         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 287         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 288         if (start>end || end-start < 4*sizeof(size_t)) return;
 289         a = (size_t *)(base + start);
 290         z = (size_t *)(base + end);
 291         a[-2] = 1;
 292         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 293         z[1] = 1;
 294         free(a);
 295 }
 296
 297 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
 298 {
 299         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 300                 if (ph->p_type!=PT_LOAD) continue;
 301                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 302                 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 303                 reclaim(base, ph->p_vaddr+ph->p_memsz,
 304                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 305         }
 306 }
 307
 308 static void *map_library(int fd, struct dso *dso)
 309 {
 310         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 311         void *allocated_buf=0;
 312         size_t phsize;
 313         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 314         size_t this_min, this_max;
 315         off_t off_start;
 316         Ehdr *eh;
 317         Phdr *ph, *ph0;
 318         unsigned prot;
 319         unsigned char *map=MAP_FAILED, *base;
 320         size_t dyn=0;
 321         size_t tls_image=0;
 322         size_t i;
 323
 324         ssize_t l = read(fd, buf, sizeof buf);
 325         eh = buf;
 326         if (l<0) return 0;
 327         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 328                 goto noexec;
 329         phsize = eh->e_phentsize * eh->e_phnum;
 330         if (phsize > sizeof buf - sizeof *eh) {
 331                 allocated_buf = malloc(phsize);
 332                 if (!allocated_buf) return 0;
 333                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 334                 if (l < 0) goto error;
 335                 if (l != phsize) goto noexec;
 336                 ph = ph0 = allocated_buf;
 337         } else if (eh->e_phoff + phsize > l) {
 338                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 339                 if (l < 0) goto error;
 340                 if (l != phsize) goto noexec;
 341                 ph = ph0 = (void *)(buf + 1);
 342         } else {
 343                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 344         }
 345         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 346                 if (ph->p_type == PT_DYNAMIC)
 347                         dyn = ph->p_vaddr;
 348                 if (ph->p_type == PT_TLS) {
 349                         tls_image = ph->p_vaddr;
 350                         dso->tls_align = ph->p_align;
 351                         dso->tls_len = ph->p_filesz;
 352                         dso->tls_size = ph->p_memsz;
 353                 }
 354                 if (ph->p_type != PT_LOAD) continue;
 355                 if (ph->p_vaddr < addr_min) {
 356                         addr_min = ph->p_vaddr;
 357                         off_start = ph->p_offset;
 358                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 359                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 360                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 361                 }
 362                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 363                         addr_max = ph->p_vaddr+ph->p_memsz;
 364                 }
 365         }
 366         if (!dyn) goto noexec;
 367         addr_max += PAGE_SIZE-1;
 368         addr_max &= -PAGE_SIZE;
 369         addr_min &= -PAGE_SIZE;
 370         off_start &= -PAGE_SIZE;
 371         map_len = addr_max - addr_min + off_start;
 372         /* The first time, we map too much, possibly even more than
 373          * the length of the file. This is okay because we will not
 374          * use the invalid part; we just need to reserve the right
 375          * amount of virtual address space to map over later. */
 376         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 377         if (map==MAP_FAILED) goto error;
 378         /* If the loaded file is not relocatable and the requested address is
 379          * not available, then the load operation must fail. */
 380         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 381                 errno = EBUSY;
 382                 goto error;
 383         }
 384         base = map - addr_min;
 385         dso->phdr = 0;
 386         dso->phnum = 0;
 387         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 388                 if (ph->p_type != PT_LOAD) continue;
 389                 /* Check if the programs headers are in this load segment, and
 390                  * if so, record the address for use by dl_iterate_phdr. */
 391                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 392                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 393                         dso->phdr = (void *)(base + ph->p_vaddr
 394                                 + (eh->e_phoff-ph->p_offset));
 395                         dso->phnum = eh->e_phnum;
 396                 }
 397                 /* Reuse the existing mapping for the lowest-address LOAD */
 398                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 399                 this_min = ph->p_vaddr & -PAGE_SIZE;
 400                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 401                 off_start = ph->p_offset & -PAGE_SIZE;
 402                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 403                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 404                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 405                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 406                         goto error;
 407                 if (ph->p_memsz > ph->p_filesz) {
 408                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 409                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 410                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 411                         if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
 412                                 goto error;
 413                 }
 414         }
 415         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 416                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 417                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 418                                 goto error;
 419                         break;
 420                 }
 421         if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
 422         dso->map = map;
 423         dso->map_len = map_len;
 424         dso->base = base;
 425         dso->dynv = (void *)(base+dyn);
 426         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 427         free(allocated_buf);
 428         return map;
 429 noexec:
 430         errno = ENOEXEC;
 431 error:
 432         if (map!=MAP_FAILED) munmap(map, map_len);
 433         free(allocated_buf);
 434         return 0;
 435 }
 436
 437 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 438 {
 439         size_t l;
 440         int fd;
 441         for (;;) {
 442                 s += strspn(s, ":\n");
 443                 l = strcspn(s, ":\n");
 444                 if (l-1 >= INT_MAX) return -1;
 445                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 446                         continue;
 447                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 448                 s += l;
 449         }
 450 }
 451
 452 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 453 {
 454         size_t n, l;
 455         const char *s, *t, *origin;
 456         char *d;
 457         if (p->rpath) return 0;
 458         if (!p->rpath_orig) return -1;
 459         if (!strchr(p->rpath_orig, '$')) {
 460                 p->rpath = p->rpath_orig;
 461                 return 0;
 462         }
 463         n = 0;
 464         s = p->rpath_orig;
 465         while ((t=strstr(s, "$ORIGIN")) || (t=strstr(s, "${ORIGIN}"))) {
 466                 s = t+1;
 467                 n++;
 468         }
 469         if (n > SSIZE_MAX/PATH_MAX) return -1;
 470
 471         if (p->kernel_mapped) {
 472                 /* $ORIGIN searches cannot be performed for the main program
 473                  * when it is suid/sgid/AT_SECURE. This is because the
 474                  * pathname is under the control of the caller of execve.
 475                  * For libraries, however, $ORIGIN can be processed safely
 476                  * since the library's pathname came from a trusted source
 477                  * (either system paths or a call to dlopen). */
 478                 if (libc.secure)
 479                         return -1;
 480                 if (readlink("/proc/self/exe", buf, buf_size) >= buf_size)
 481                         return -1;
 482                 origin = buf;
 483         } else {
 484                 origin = p->name;
 485         }
 486         t = strrchr(origin, '/');
 487         l = t ? t-origin : 0;
 488         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 489         if (!p->rpath) return -1;
 490
 491         d = p->rpath;
 492         s = p->rpath_orig;
 493         while ((t=strstr(s, "$ORIGIN")) || (t=strstr(s, "${ORIGIN}"))) {
 494                 memcpy(d, s, t-s);
 495                 d += t-s;
 496                 memcpy(d, origin, l);
 497                 d += l;
 498                 s = t + 7 + 2*(t[1]=='{');
 499         }
 500         strcpy(d, s);
 501         return 0;
 502 }
 503
 504 static void decode_dyn(struct dso *p)
 505 {
 506         size_t dyn[DYN_CNT] = {0};
 507         decode_vec(p->dynv, dyn, DYN_CNT);
 508         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 509         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 510         if (dyn[0]&(1<<DT_HASH))
 511                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 512         if (dyn[0]&(1<<DT_RPATH))
 513                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 514         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 515                 p->ghashtab = (void *)(p->base + *dyn);
 516         if (search_vec(p->dynv, dyn, DT_VERSYM))
 517                 p->versym = (void *)(p->base + *dyn);
 518 }
 519
 520 static struct dso *load_library(const char *name, struct dso *needed_by)
 521 {
 522         char buf[2*NAME_MAX+2];
 523         const char *pathname;
 524         unsigned char *map;
 525         struct dso *p, temp_dso = {0};
 526         int fd;
 527         struct stat st;
 528         size_t alloc_size;
 529         int n_th = 0;
 530         int is_self = 0;
 531
 532         /* Catch and block attempts to reload the implementation itself */
 533         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 534                 static const char *rp, reserved[] =
 535                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 536                 char *z = strchr(name, '.');
 537                 if (z) {
 538                         size_t l = z-name;
 539                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 540                         if (*rp) {
 541                                 if (ldd_mode) {
 542                                         /* Track which names have been resolved
 543                                          * and only report each one once. */
 544                                         static unsigned reported;
 545                                         unsigned mask = 1U<<(rp-reserved);
 546                                         if (!(reported & mask)) {
 547                                                 reported |= mask;
 548                                                 dprintf(1, "\t%s => %s (%p)\n",
 549                                                         name, ldso->name,
 550                                                         ldso->base);
 551                                         }
 552                                 }
 553                                 is_self = 1;
 554                         }
 555                 }
 556         }
 557         if (!strcmp(name, ldso->name)) is_self = 1;
 558         if (is_self) {
 559                 if (!ldso->prev) {
 560                         tail->next = ldso;
 561                         ldso->prev = tail;
 562                         tail = ldso->next ? ldso->next : ldso;
 563                 }
 564                 return ldso;
 565         }
 566         if (strchr(name, '/')) {
 567                 pathname = name;
 568                 fd = open(name, O_RDONLY|O_CLOEXEC);
 569         } else {
 570                 /* Search for the name to see if it's already loaded */
 571                 for (p=head->next; p; p=p->next) {
 572                         if (p->shortname && !strcmp(p->shortname, name)) {
 573                                 p->refcnt++;
 574                                 return p;
 575                         }
 576                 }
 577                 if (strlen(name) > NAME_MAX) return 0;
 578                 fd = -1;
 579                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 580                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 581                         if (!fixup_rpath(p, buf, sizeof buf))
 582                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 583                 if (fd < 0) {
 584                         if (!sys_path) {
 585                                 char *prefix = 0;
 586                                 size_t prefix_len;
 587                                 if (ldso->name[0]=='/') {
 588                                         char *s, *t, *z;
 589                                         for (s=t=z=ldso->name; *s; s++)
 590                                                 if (*s=='/') z=t, t=s;
 591                                         prefix_len = z-ldso->name;
 592                                         if (prefix_len < PATH_MAX)
 593                                                 prefix = ldso->name;
 594                                 }
 595                                 if (!prefix) {
 596                                         prefix = "";
 597                                         prefix_len = 0;
 598                                 }
 599                                 char etc_ldso_path[prefix_len + 1
 600                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 601                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 602                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 603                                         (int)prefix_len, prefix);
 604                                 FILE *f = fopen(etc_ldso_path, "rbe");
 605                                 if (f) {
 606                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 607                                                 free(sys_path);
 608                                                 sys_path = "";
 609                                         }
 610                                         fclose(f);
 611                                 }
 612                         }
 613                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 614                         fd = path_open(name, sys_path, buf, sizeof buf);
 615                 }
 616                 pathname = buf;
 617         }
 618         if (fd < 0) return 0;
 619         if (fstat(fd, &st) < 0) {
 620                 close(fd);
 621                 return 0;
 622         }
 623         for (p=head->next; p; p=p->next) {
 624                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 625                         /* If this library was previously loaded with a
 626                          * pathname but a search found the same inode,
 627                          * setup its shortname so it can be found by name. */
 628                         if (!p->shortname && pathname != name)
 629                                 p->shortname = strrchr(p->name, '/')+1;
 630                         close(fd);
 631                         p->refcnt++;
 632                         return p;
 633                 }
 634         }
 635         map = noload ? 0 : map_library(fd, &temp_dso);
 636         close(fd);
 637         if (!map) return 0;
 638
 639         /* Allocate storage for the new DSO. When there is TLS, this
 640          * storage must include a reservation for all pre-existing
 641          * threads to obtain copies of both the new TLS, and an
 642          * extended DTV capable of storing an additional slot for
 643          * the newly-loaded DSO. */
 644         alloc_size = sizeof *p + strlen(pathname) + 1;
 645         if (runtime && temp_dso.tls_image) {
 646                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 647                         + sizeof(void *) * (tls_cnt+3);
 648                 n_th = libc.threads_minus_1 + 1;
 649                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 650                 else alloc_size += n_th * per_th;
 651         }
 652         p = calloc(1, alloc_size);
 653         if (!p) {
 654                 munmap(map, temp_dso.map_len);
 655                 return 0;
 656         }
 657         memcpy(p, &temp_dso, sizeof temp_dso);
 658         decode_dyn(p);
 659         p->dev = st.st_dev;
 660         p->ino = st.st_ino;
 661         p->refcnt = 1;
 662         p->needed_by = needed_by;
 663         p->name = p->buf;
 664         strcpy(p->name, pathname);
 665         /* Add a shortname only if name arg was not an explicit pathname. */
 666         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 667         if (p->tls_image) {
 668                 if (runtime && !__pthread_self_init()) {
 669                         munmap(map, p->map_len);
 670                         free(p);
 671                         return 0;
 672                 }
 673                 p->tls_id = ++tls_cnt;
 674                 tls_align = MAXP2(tls_align, p->tls_align);
 675 #ifdef TLS_ABOVE_TP
 676                 p->tls_offset = tls_offset + ( (tls_align-1) &
 677                         -(tls_offset + (uintptr_t)p->tls_image) );
 678                 tls_offset += p->tls_size;
 679 #else
 680                 tls_offset += p->tls_size + p->tls_align - 1;
 681                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 682                         & (p->tls_align-1);
 683                 p->tls_offset = tls_offset;
 684 #endif
 685                 p->new_dtv = (void *)(-sizeof(size_t) &
 686                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 687                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 688         }
 689
 690         tail->next = p;
 691         p->prev = tail;
 692         tail = p;
 693
 694         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 695
 696         return p;
 697 }
 698
 699 static void load_deps(struct dso *p)
 700 {
 701         size_t i, ndeps=0;
 702         struct dso ***deps = &p->deps, **tmp, *dep;
 703         for (; p; p=p->next) {
 704                 for (i=0; p->dynv[i]; i+=2) {
 705                         if (p->dynv[i] != DT_NEEDED) continue;
 706                         dep = load_library(p->strings + p->dynv[i+1], p);
 707                         if (!dep) {
 708                                 snprintf(errbuf, sizeof errbuf,
 709                                         "Error loading shared library %s: %m (needed by %s)",
 710                                         p->strings + p->dynv[i+1], p->name);
 711                                 if (runtime) longjmp(*rtld_fail, 1);
 712                                 dprintf(2, "%s\n", errbuf);
 713                                 ldso_fail = 1;
 714                                 continue;
 715                         }
 716                         if (runtime) {
 717                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 718                                 if (!tmp) longjmp(*rtld_fail, 1);
 719                                 tmp[ndeps++] = dep;
 720                                 tmp[ndeps] = 0;
 721                                 *deps = tmp;
 722                         }
 723                 }
 724         }
 725 }
 726
 727 static void load_preload(char *s)
 728 {
 729         int tmp;
 730         char *z;
 731         for (z=s; *z; s=z) {
 732                 for (   ; *s && isspace(*s); s++);
 733                 for (z=s; *z && !isspace(*z); z++);
 734                 tmp = *z;
 735                 *z = 0;
 736                 load_library(s, 0);
 737                 *z = tmp;
 738         }
 739 }
 740
 741 static void make_global(struct dso *p)
 742 {
 743         for (; p; p=p->next) p->global = 1;
 744 }
 745
 746 static void reloc_all(struct dso *p)
 747 {
 748         size_t dyn[DYN_CNT] = {0};
 749         for (; p; p=p->next) {
 750                 if (p->relocated) continue;
 751                 decode_vec(p->dynv, dyn, DYN_CNT);
 752 #ifdef NEED_ARCH_RELOCS
 753                 do_arch_relocs(p, head);
 754 #endif
 755                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 756                         2+(dyn[DT_PLTREL]==DT_RELA));
 757                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 758                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 759                 p->relocated = 1;
 760         }
 761 }
 762
 763 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 764 {
 765         for (; cnt--; ph = (void *)((char *)ph + stride))
 766                 if (ph->p_type == PT_DYNAMIC)
 767                         return ph->p_vaddr;
 768         return 0;
 769 }
 770
 771 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 772 {
 773         size_t min_addr = -1, max_addr = 0;
 774         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 775                 if (ph->p_type != PT_LOAD) continue;
 776                 if (ph->p_vaddr < min_addr)
 777                         min_addr = ph->p_vaddr;
 778                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 779                         max_addr = ph->p_vaddr+ph->p_memsz;
 780         }
 781         min_addr &= -PAGE_SIZE;
 782         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 783         p->map = p->base + min_addr;
 784         p->map_len = max_addr - min_addr;
 785 }
 786
 787 static void do_fini()
 788 {
 789         struct dso *p;
 790         size_t dyn[DYN_CNT] = {0};
 791         for (p=fini_head; p; p=p->fini_next) {
 792                 if (!p->constructed) continue;
 793                 decode_vec(p->dynv, dyn, DYN_CNT);
 794                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 795                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 796                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 797                         while (n--) ((void (*)(void))*--fn)();
 798                 }
 799 #ifndef NO_LEGACY_INITFINI
 800                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 801                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 802 #endif
 803         }
 804 }
 805
 806 static void do_init_fini(struct dso *p)
 807 {
 808         size_t dyn[DYN_CNT] = {0};
 809         int need_locking = libc.threads_minus_1;
 810         /* Allow recursive calls that arise when a library calls
 811          * dlopen from one of its constructors, but block any
 812          * other threads until all ctors have finished. */
 813         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 814         for (; p; p=p->prev) {
 815                 if (p->constructed) continue;
 816                 p->constructed = 1;
 817                 decode_vec(p->dynv, dyn, DYN_CNT);
 818                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 819                         p->fini_next = fini_head;
 820                         fini_head = p;
 821                 }
 822 #ifndef NO_LEGACY_INITFINI
 823                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 824                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 825 #endif
 826                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 827                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 828                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 829                         while (n--) ((void (*)(void))*fn++)();
 830                 }
 831                 if (!need_locking && libc.threads_minus_1) {
 832                         need_locking = 1;
 833                         pthread_mutex_lock(&init_fini_lock);
 834                 }
 835         }
 836         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 837 }
 838
 839 void _dl_debug_state(void)
 840 {
 841 }
 842
 843 void __reset_tls()
 844 {
 845         pthread_t self = __pthread_self();
 846         struct dso *p;
 847         for (p=head; p; p=p->next) {
 848                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 849                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 850                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 851                         p->tls_size - p->tls_len);
 852                 if (p->tls_id == (size_t)self->dtv[0]) break;
 853         }
 854 }
 855
 856 void *__copy_tls(unsigned char *mem)
 857 {
 858         pthread_t td;
 859         struct dso *p;
 860
 861         if (!tls_cnt) return mem;
 862
 863         void **dtv = (void *)mem;
 864         dtv[0] = (void *)tls_cnt;
 865
 866 #ifdef TLS_ABOVE_TP
 867         mem += sizeof(void *) * (tls_cnt+1);
 868         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 869         td = (pthread_t)mem;
 870         mem += sizeof(struct pthread);
 871
 872         for (p=head; p; p=p->next) {
 873                 if (!p->tls_id) continue;
 874                 dtv[p->tls_id] = mem + p->tls_offset;
 875                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 876         }
 877 #else
 878         mem += libc.tls_size - sizeof(struct pthread);
 879         mem -= (uintptr_t)mem & (tls_align-1);
 880         td = (pthread_t)mem;
 881
 882         for (p=head; p; p=p->next) {
 883                 if (!p->tls_id) continue;
 884                 dtv[p->tls_id] = mem - p->tls_offset;
 885                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 886         }
 887 #endif
 888         td->dtv = dtv;
 889         return td;
 890 }
 891
 892 void *__tls_get_addr(size_t *v)
 893 {
 894         pthread_t self = __pthread_self();
 895         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 896                 return (char *)self->dtv[v[0]]+v[1];
 897
 898         /* Block signals to make accessing new TLS async-signal-safe */
 899         sigset_t set;
 900         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 901         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 902                 pthread_sigmask(SIG_SETMASK, &set, 0);
 903                 return (char *)self->dtv[v[0]]+v[1];
 904         }
 905
 906         /* This is safe without any locks held because, if the caller
 907          * is able to request the Nth entry of the DTV, the DSO list
 908          * must be valid at least that far out and it was synchronized
 909          * at program startup or by an already-completed call to dlopen. */
 910         struct dso *p;
 911         for (p=head; p->tls_id != v[0]; p=p->next);
 912
 913         /* Get new DTV space from new DSO if needed */
 914         if (v[0] > (size_t)self->dtv[0]) {
 915                 void **newdtv = p->new_dtv +
 916                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 917                 memcpy(newdtv, self->dtv,
 918                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 919                 newdtv[0] = (void *)v[0];
 920                 self->dtv = newdtv;
 921         }
 922
 923         /* Get new TLS memory from new DSO */
 924         unsigned char *mem = p->new_tls +
 925                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 926         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 927         self->dtv[v[0]] = mem;
 928         memcpy(mem, p->tls_image, p->tls_len);
 929         pthread_sigmask(SIG_SETMASK, &set, 0);
 930         return mem + v[1];
 931 }
 932
 933 static void update_tls_size()
 934 {
 935         libc.tls_size = ALIGN(
 936                 (1+tls_cnt) * sizeof(void *) +
 937                 tls_offset +
 938                 sizeof(struct pthread) +
 939                 tls_align * 2,
 940         tls_align);
 941 }
 942
 943 void *__dynlink(int argc, char **argv)
 944 {
 945         size_t aux[AUX_CNT] = {0};
 946         size_t i;
 947         Phdr *phdr;
 948         Ehdr *ehdr;
 949         static struct dso builtin_dsos[3];
 950         struct dso *const app = builtin_dsos+0;
 951         struct dso *const lib = builtin_dsos+1;
 952         struct dso *const vdso = builtin_dsos+2;
 953         char *env_preload=0;
 954         size_t vdso_base;
 955         size_t *auxv;
 956         char **envp = argv+argc+1;
 957
 958         /* Find aux vector just past environ[] */
 959         for (i=argc+1; argv[i]; i++)
 960                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 961                         env_path = argv[i]+16;
 962                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 963                         env_preload = argv[i]+11;
 964         auxv = (void *)(argv+i+1);
 965
 966         decode_vec(auxv, aux, AUX_CNT);
 967
 968         /* Only trust user/env if kernel says we're not suid/sgid */
 969         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 970           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 971                 env_path = 0;
 972                 env_preload = 0;
 973                 libc.secure = 1;
 974         }
 975
 976         /* If the dynamic linker was invoked as a program itself, AT_BASE
 977          * will not be set. In that case, we assume the base address is
 978          * the start of the page containing the PHDRs; I don't know any
 979          * better approach... */
 980         if (!aux[AT_BASE]) {
 981                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 982                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 983         }
 984
 985         /* The dynamic linker load address is passed by the kernel
 986          * in the AUX vector, so this is easy. */
 987         lib->base = (void *)aux[AT_BASE];
 988         lib->name = lib->shortname = "libc.so";
 989         lib->global = 1;
 990         lib->kernel_mapped = 1;
 991         ehdr = (void *)lib->base;
 992         lib->phnum = ehdr->e_phnum;
 993         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
 994         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
 995         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
 996                 ehdr->e_phnum, ehdr->e_phentsize));
 997         decode_dyn(lib);
 998
 999         if (aux[AT_PHDR]) {
1000                 size_t interp_off = 0;
1001                 size_t tls_image = 0;
1002                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1003                 app->phdr = phdr = (void *)aux[AT_PHDR];
1004                 app->phnum = aux[AT_PHNUM];
1005                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1006                         if (phdr->p_type == PT_PHDR)
1007                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1008                         else if (phdr->p_type == PT_INTERP)
1009                                 interp_off = (size_t)phdr->p_vaddr;
1010                         else if (phdr->p_type == PT_TLS) {
1011                                 tls_image = phdr->p_vaddr;
1012                                 app->tls_len = phdr->p_filesz;
1013                                 app->tls_size = phdr->p_memsz;
1014                                 app->tls_align = phdr->p_align;
1015                         }
1016                 }
1017                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1018                 if (interp_off) lib->name = (char *)app->base + interp_off;
1019                 if ((aux[0] & (1UL<<AT_EXECFN))
1020                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1021                         app->name = (char *)aux[AT_EXECFN];
1022                 else
1023                         app->name = argv[0];
1024                 app->kernel_mapped = 1;
1025                 app->dynv = (void *)(app->base + find_dyn(
1026                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1027                 find_map_range((void *)aux[AT_PHDR],
1028                         aux[AT_PHNUM], aux[AT_PHENT], app);
1029         } else {
1030                 int fd;
1031                 char *ldname = argv[0];
1032                 size_t l = strlen(ldname);
1033                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1034                 *argv++ = (void *)-1;
1035                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1036                 if (!argv[0]) {
1037                         dprintf(2, "musl libc/dynamic program loader\n");
1038                         dprintf(2, "usage: %s pathname%s\n", ldname,
1039                                 ldd_mode ? "" : " [args]");
1040                         _exit(1);
1041                 }
1042                 fd = open(argv[0], O_RDONLY);
1043                 if (fd < 0) {
1044                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1045                         _exit(1);
1046                 }
1047                 runtime = 1;
1048                 ehdr = (void *)map_library(fd, app);
1049                 if (!ehdr) {
1050                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1051                         _exit(1);
1052                 }
1053                 runtime = 0;
1054                 close(fd);
1055                 lib->name = ldname;
1056                 app->name = argv[0];
1057                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1058                 /* Find the name that would have been used for the dynamic
1059                  * linker had ldd not taken its place. */
1060                 if (ldd_mode) {
1061                         for (i=0; i<app->phnum; i++) {
1062                                 if (app->phdr[i].p_type == PT_INTERP)
1063                                         lib->name = (void *)(app->base
1064                                                 + app->phdr[i].p_vaddr);
1065                         }
1066                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1067                 }
1068         }
1069         if (app->tls_size) {
1070                 app->tls_id = tls_cnt = 1;
1071 #ifdef TLS_ABOVE_TP
1072                 app->tls_offset = 0;
1073                 tls_offset = app->tls_size
1074                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1075                         & (app->tls_align-1) );
1076 #else
1077                 tls_offset = app->tls_offset = app->tls_size
1078                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1079                         & (app->tls_align-1) );
1080 #endif
1081                 tls_align = MAXP2(tls_align, app->tls_align);
1082         }
1083         app->global = 1;
1084         decode_dyn(app);
1085
1086         /* Attach to vdso, if provided by the kernel */
1087         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1088                 ehdr = (void *)vdso_base;
1089                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1090                 vdso->phnum = ehdr->e_phnum;
1091                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1092                         if (phdr->p_type == PT_DYNAMIC)
1093                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1094                         if (phdr->p_type == PT_LOAD)
1095                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1096                 }
1097                 vdso->name = "";
1098                 vdso->shortname = "linux-gate.so.1";
1099                 vdso->global = 1;
1100                 decode_dyn(vdso);
1101                 vdso->prev = lib;
1102                 lib->next = vdso;
1103         }
1104
1105         /* Initial dso chain consists only of the app. We temporarily
1106          * append the dynamic linker/libc so we can relocate it, then
1107          * restore the initial chain in preparation for loading third
1108          * party libraries (preload/needed). */
1109         head = tail = app;
1110         ldso = lib;
1111         app->next = lib;
1112         reloc_all(lib);
1113         app->next = 0;
1114
1115         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1116
1117         /* Donate unused parts of app and library mapping to malloc */
1118         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1119         ehdr = (void *)lib->base;
1120         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1121                 ehdr->e_phentsize, ehdr->e_phnum);
1122
1123         /* Load preload/needed libraries, add their symbols to the global
1124          * namespace, and perform all remaining relocations. The main
1125          * program must be relocated LAST since it may contain copy
1126          * relocations which depend on libraries' relocations. */
1127         if (env_preload) load_preload(env_preload);
1128         load_deps(app);
1129         make_global(app);
1130
1131         reloc_all(app->next);
1132         reloc_all(app);
1133
1134         update_tls_size();
1135         if (tls_cnt) {
1136                 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1137                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1138                 if (mem==MAP_FAILED ||
1139                     !__install_initial_tls(__copy_tls(mem))) {
1140                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1141                                 argv[0], libc.tls_size);
1142                         _exit(127);
1143                 }
1144         }
1145
1146         if (ldso_fail) _exit(127);
1147         if (ldd_mode) _exit(0);
1148
1149         /* Switch to runtime mode: any further failures in the dynamic
1150          * linker are a reportable failure rather than a fatal startup
1151          * error. If the dynamic loader (dlopen) will not be used, free
1152          * all memory used by the dynamic linker. */
1153         runtime = 1;
1154
1155 #ifndef DYNAMIC_IS_RO
1156         for (i=0; app->dynv[i]; i+=2)
1157                 if (app->dynv[i]==DT_DEBUG)
1158                         app->dynv[i+1] = (size_t)&debug;
1159 #endif
1160         debug.ver = 1;
1161         debug.bp = _dl_debug_state;
1162         debug.head = head;
1163         debug.base = lib->base;
1164         debug.state = 0;
1165         _dl_debug_state();
1166
1167         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1168         __init_libc(envp, argv[0]);
1169         atexit(do_fini);
1170         errno = 0;
1171         do_init_fini(tail);
1172
1173         return (void *)aux[AT_ENTRY];
1174 }
1175
1176 void *dlopen(const char *file, int mode)
1177 {
1178         struct dso *volatile p, *orig_tail, *next;
1179         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1180         size_t i;
1181         int cs;
1182         jmp_buf jb;
1183
1184         if (!file) return head;
1185
1186         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1187         pthread_rwlock_wrlock(&lock);
1188         __inhibit_ptc();
1189
1190         p = 0;
1191         orig_tls_cnt = tls_cnt;
1192         orig_tls_offset = tls_offset;
1193         orig_tls_align = tls_align;
1194         orig_tail = tail;
1195         noload = mode & RTLD_NOLOAD;
1196
1197         rtld_fail = &jb;
1198         if (setjmp(*rtld_fail)) {
1199                 /* Clean up anything new that was (partially) loaded */
1200                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1201                         if (p->deps[i]->global < 0)
1202                                 p->deps[i]->global = 0;
1203                 for (p=orig_tail->next; p; p=next) {
1204                         next = p->next;
1205                         munmap(p->map, p->map_len);
1206                         free(p->deps);
1207                         free(p);
1208                 }
1209                 tls_cnt = orig_tls_cnt;
1210                 tls_offset = orig_tls_offset;
1211                 tls_align = orig_tls_align;
1212                 tail = orig_tail;
1213                 tail->next = 0;
1214                 p = 0;
1215                 errflag = 1;
1216                 goto end;
1217         } else p = load_library(file, 0);
1218
1219         if (!p) {
1220                 snprintf(errbuf, sizeof errbuf, noload ?
1221                         "Library %s is not already loaded" :
1222                         "Error loading shared library %s: %m",
1223                         file);
1224                 errflag = 1;
1225                 goto end;
1226         }
1227
1228         /* First load handling */
1229         if (!p->deps) {
1230                 load_deps(p);
1231                 if (p->deps) for (i=0; p->deps[i]; i++)
1232                         if (!p->deps[i]->global)
1233                                 p->deps[i]->global = -1;
1234                 if (!p->global) p->global = -1;
1235                 reloc_all(p);
1236                 if (p->deps) for (i=0; p->deps[i]; i++)
1237                         if (p->deps[i]->global < 0)
1238                                 p->deps[i]->global = 0;
1239                 if (p->global < 0) p->global = 0;
1240         }
1241
1242         if (mode & RTLD_GLOBAL) {
1243                 if (p->deps) for (i=0; p->deps[i]; i++)
1244                         p->deps[i]->global = 1;
1245                 p->global = 1;
1246         }
1247
1248         update_tls_size();
1249
1250         if (ssp_used) __init_ssp(libc.auxv);
1251
1252         _dl_debug_state();
1253         orig_tail = tail;
1254 end:
1255         __release_ptc();
1256         if (p) gencnt++;
1257         pthread_rwlock_unlock(&lock);
1258         if (p) do_init_fini(orig_tail);
1259         pthread_setcancelstate(cs, 0);
1260         return p;
1261 }
1262
1263 static int invalid_dso_handle(void *h)
1264 {
1265         struct dso *p;
1266         for (p=head; p; p=p->next) if (h==p) return 0;
1267         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1268         errflag = 1;
1269         return 1;
1270 }
1271
1272 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1273 {
1274         size_t i;
1275         uint32_t h = 0, gh = 0;
1276         Sym *sym;
1277         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1278                 if (p == RTLD_DEFAULT) {
1279                         p = head;
1280                 } else if (p == RTLD_NEXT) {
1281                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1282                         if (!p) p=head;
1283                         p = p->next;
1284                 }
1285                 struct symdef def = find_sym(p, s, 0);
1286                 if (!def.sym) goto failed;
1287                 if ((def.sym->st_info&0xf) == STT_TLS)
1288                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1289                 return def.dso->base + def.sym->st_value;
1290         }
1291         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1292                 return 0;
1293         if (p->ghashtab) {
1294                 gh = gnu_hash(s);
1295                 sym = gnu_lookup(s, gh, p);
1296         } else {
1297                 h = sysv_hash(s);
1298                 sym = sysv_lookup(s, h, p);
1299         }
1300         if (sym && (sym->st_info&0xf) == STT_TLS)
1301                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1302         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1303                 return p->base + sym->st_value;
1304         if (p->deps) for (i=0; p->deps[i]; i++) {
1305                 if (p->deps[i]->ghashtab) {
1306                         if (!gh) gh = gnu_hash(s);
1307                         sym = gnu_lookup(s, gh, p->deps[i]);
1308                 } else {
1309                         if (!h) h = sysv_hash(s);
1310                         sym = sysv_lookup(s, h, p->deps[i]);
1311                 }
1312                 if (sym && (sym->st_info&0xf) == STT_TLS)
1313                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1314                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1315                         return p->deps[i]->base + sym->st_value;
1316         }
1317 failed:
1318         errflag = 1;
1319         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1320         return 0;
1321 }
1322
1323 int __dladdr(void *addr, Dl_info *info)
1324 {
1325         struct dso *p;
1326         Sym *sym;
1327         uint32_t nsym;
1328         char *strings;
1329         size_t i;
1330         void *best = 0;
1331         char *bestname;
1332
1333         pthread_rwlock_rdlock(&lock);
1334         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1335         pthread_rwlock_unlock(&lock);
1336
1337         if (!p) return 0;
1338
1339         sym = p->syms;
1340         strings = p->strings;
1341         if (p->hashtab) {
1342                 nsym = p->hashtab[1];
1343         } else {
1344                 uint32_t *buckets;
1345                 uint32_t *hashval;
1346                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1347                 sym += p->ghashtab[1];
1348                 for (i = 0; i < p->ghashtab[0]; i++) {
1349                         if (buckets[i] > nsym)
1350                                 nsym = buckets[i];
1351                 }
1352                 if (nsym) {
1353                         nsym -= p->ghashtab[1];
1354                         hashval = buckets + p->ghashtab[0] + nsym;
1355                         do nsym++;
1356                         while (!(*hashval++ & 1));
1357                 }
1358         }
1359
1360         for (; nsym; nsym--, sym++) {
1361                 if (sym->st_value
1362                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1363                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1364                         void *symaddr = p->base + sym->st_value;
1365                         if (symaddr > addr || symaddr < best)
1366                                 continue;
1367                         best = symaddr;
1368                         bestname = strings + sym->st_name;
1369                         if (addr == symaddr)
1370                                 break;
1371                 }
1372         }
1373
1374         if (!best) return 0;
1375
1376         info->dli_fname = p->name;
1377         info->dli_fbase = p->base;
1378         info->dli_sname = bestname;
1379         info->dli_saddr = best;
1380
1381         return 1;
1382 }
1383
1384 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1385 {
1386         void *res;
1387         pthread_rwlock_rdlock(&lock);
1388         res = do_dlsym(p, s, ra);
1389         pthread_rwlock_unlock(&lock);
1390         return res;
1391 }
1392
1393 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1394 {
1395         struct dso *current;
1396         struct dl_phdr_info info;
1397         int ret = 0;
1398         for(current = head; current;) {
1399                 info.dlpi_addr      = (uintptr_t)current->base;
1400                 info.dlpi_name      = current->name;
1401                 info.dlpi_phdr      = current->phdr;
1402                 info.dlpi_phnum     = current->phnum;
1403                 info.dlpi_adds      = gencnt;
1404                 info.dlpi_subs      = 0;
1405                 info.dlpi_tls_modid = current->tls_id;
1406                 info.dlpi_tls_data  = current->tls_image;
1407
1408                 ret = (callback)(&info, sizeof (info), data);
1409
1410                 if (ret != 0) break;
1411
1412                 pthread_rwlock_rdlock(&lock);
1413                 current = current->next;
1414                 pthread_rwlock_unlock(&lock);
1415         }
1416         return ret;
1417 }
1418 #else
1419 static int invalid_dso_handle(void *h)
1420 {
1421         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1422         errflag = 1;
1423         return 1;
1424 }
1425 void *dlopen(const char *file, int mode)
1426 {
1427         return 0;
1428 }
1429 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1430 {
1431         return 0;
1432 }
1433 int __dladdr (void *addr, Dl_info *info)
1434 {
1435         return 0;
1436 }
1437 #endif
1438
1439 int __dlinfo(void *dso, int req, void *res)
1440 {
1441         if (invalid_dso_handle(dso)) return -1;
1442         if (req != RTLD_DI_LINKMAP) {
1443                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1444                 errflag = 1;
1445                 return -1;
1446         }
1447         *(struct link_map **)res = dso;
1448         return 0;
1449 }
1450
1451 char *dlerror()
1452 {
1453         if (!errflag) return 0;
1454         errflag = 0;
1455         return errbuf;
1456 }
1457
1458 int dlclose(void *p)
1459 {
1460         return invalid_dso_handle(p);
1461 }